(Reuters) – The outcome of the U.S. presidential election hung in the balance on Thursday as five swing states continued to count their ballots.

To capture the White House, a candidate must amass at least 270 votes in the Electoral College.

Edison Research gave Democratic challenger Biden a 243 against 213 lead over Republican President Donald Trump in Electoral College votes. Other networks said Biden had won Wisconsin, which would give him another 10 votes.

Results in Pennsylvania (20 electoral votes), Georgia (16), North Carolina (15), Arizona (11) and Nevada (6) remained uncertain as of Thursday afternoon, according to Edison Research.

ARIZONA

Biden led by 2.4 percentage points as of Thursday afternoon, or more than 68,000 votes, with about 14% of the vote left to be counted.

More results from densely populated Maricopa County, which includes Phoenix, were not expected until 7 p.m. local time (9 p.m. EST, 0200 Friday GMT), the county elections department said.

There were at least 275,000 ballots in the county left to be counted, the elections department said. Biden was leading by 4 percentage points in the votes counted so far, indicating he was in a strong position to maintain his lead.

GEORGIA

Trump held onto to a lead of 0.3 percentage points, or 12,835 votes, with 2% percent of the vote left to be counted.

Counting was continuing on Thursday afternoon, with just 47,000 outstanding ballots, Georgia Secretary of State Brad Raffensperger said in a press conference.

NEVADA

Biden led Trump by 11,438 votes, or 0.9 percentage points, with about 12% of the vote left to be counted.

The state’s biggest county, Clark, expected to count the majority of its mail ballots by Saturday or Sunday, but would continue to count certain ballots after the weekend, according to its registrar, Joe Gloria.

All properly received ballots will be counted for up to nine days after the election, but the exact number left to be counted was unknown, said Nevada Secretary of State Barbara Cegavske.

The outstanding votes are mail-in ballots and those cast by voters who registered to vote at polling place on Election Day, she said.

NORTH CAROLINA

Trump led by more than 76,000 votes, or 1.4 points, with about 5% of the vote uncounted.

State officials have said a full result would not be known until next week. The state allows mail-in ballots postmarked by Tuesday to be counted if they are received by Nov. 12.

PENNSYLVANIA

Trump led by 1.7 percentage points, or more than 108,000 votes, with 8% of the vote outstanding.

About 370,000 ballots were still in the process of being counted on Thursday, according to the Department of State’s website, giving Biden a chance to catch Trump if enough of them were from Democratically friendly areas such as Philadelphia. Pennsylvania Secretary of State Kathy Boockvar said she expected the “overwhelming majority” to be counted by the end of Thursday.

Philadelphia County reported more than 252,000 ballots were cast by mail but did say how many remained to be counted.

A final count may not be available until at least Friday as Pennsylvania can accept mailed-in ballots up to three days after the election if they were postmarked by Tuesday.

(Reporting by Daniel Trotta and Julia Harte; Editing by Scott Malone and Daniel Wallis)